Dual steam control for locomotives



Nov. 9, 1926. 1,606,612 F. W. BROWN DUAL STEAM CONTROL FOR LOCOMOTIVES Original Filed March 11, 1916 3 Sheets-Sheet 1 Nov. 9, 1926. 1,606,612

' F. W. BROWN DUAL STEAM CONTROL FOR LOCOMOTIVES Original Filed March 11, 191 5 sheets-Sheet 2 gyazw Y "W Nov. 9 192.6. 1 1,606,612

F. W. BROWN DUAL STEAMCONTROL FOR-LOCOMOTIVES Original Filed March 11, 1916 3 Sheets-$heet 3 Patented Nov. 9, 1926.

FFECE.

FREDERICK W. BROWN, 0F VIASHINGTON, DISTRICT OF COLUMBIA.

DUAL STEAM CONTROL FOR LQCOMCOTIVES.

Application filed March 11, 1916, Serial 1%. 83.678.

The present invention relates to motive power for railway engines and consists in a method of, and apparatus for, making direct use of saturated steam, on superheat engines, in order to temporarily increase the power of such engines for the purpose of starting, or during a continuous pull on heavy grades.

During the past few years, one of the greatest developments in locomotive efticiency has been brought about through the introduction and use of superheated steam, instead of saturated steam. Various types of piping arrangements are employed to accomplish the transition from saturated to superheated steam, all having for their common objective the re-heating, or superheating as it is called, of wet steam generated in the boiler.

In a general way this is done by convey ing the wet or saturated steam through a system of small pipes enclosed in large flues located in, with or between the generating flues. These superheat units, so called, fre quently consist of 3,000 feet or more of pipe, into which the wet steam is forced and distributed. By so doing, the saturated steam is gradually raised in temperature from approximately 225 degrees to as high as 500 to 600 degrees, attaining thereby a much greater expansiveness.

The main object of this process is to secure greater effectiveness from the steam generated, thereby decreasing the amount of coal that would have to be burned if saturated steam was used continuously at its normal temperature and expansiveness. With the use of superheated steam, it is possible also to maintain a lower boiler pressure, causing less strain on the fines and .bo-iler appurtenances.

There are two essentially weak features in the superheat type of engines, as has been clearly detectable in everyday operation of trains:

First: Slow in starting a train, due to distance steam has to travel from boiler to cylinders.

Second: Gradual decrease in the high temperature of superheated steam (thereby lessening its effectiveness) during a long hard pull on heavy grades, at which time the draught of engine is at its lowest point in freeing the cylinders.

Further explaining these two weaknesses Renewed August 1 1, 1922, Serial No. 581,264. r

of the present type of superheat engines, in the order named:

First: The process of superheating the wet steam does not begin until the throttle of engine is openedfor the purpose of starting engine or train. Then the saturated steam thus admitted from the boiler to main steam pipe (or dry pipe, so called) must, before it can reach the cylinders, pass into the system of superheat units of 3,000 feet or more in length and necessaril constructed with many bends in same, al of which retards the free passage of steam to cylinders. As a consequence, the engine is slow in starting, and when it does start there has been so much steam admitted to dry pipe in the forcing process of driving the steam through superheat units that the train is roughly handled. In passenger service, this is very discoinforting to travelers, and in freight service causes much damage to the freight loaded in cars.

At points where the start has to be made on a sharp ascending grade, it is frequently impossible to move heavy passenger trains or full tonnage freight trains until several attempts have been made, or until sufficient steam has reached the cylinders to provide the engine with necessary tract-ive power, or drawbar pull, so called. The drawbar pull is directly proportional to the mean effective pressure of steam in the cylinders, and depends entirely upon this, all other things being constant. It follows, therefore, that any device which tends to in crease the mean effective pressure, will also increase the drawbar pull.

WVhile superheated steam is more economical in train service after the train is in motion, it has a mean effective pressure of only 88% of the boiler pressure, whereas saturated steam has a mean effective pres sure of approximately 93% or 94%, if applied direct in engines designed for superheat steam, equipped with piston valves and much freer passages for the steam entering cylinders, than in the old style slide valve engines designed for saturated steam.

By initially utilizing the saturated steam to start a train, this increased power of approximately 7% or 8% is obtained immediately upon the opening of the throttle, thus bridging all of the superheat unit sys tem of 3,000 feet or more, and allowing the live steam from the boiler with a mean effective pressure of 93% or 94% of the full boiler pressure, topass directly into the steam chambers, thence to the cylinders, with absolutely nothing to retard its instant usage in the cylinders; the passage to be traveled by the steam so diverted being the shortest possible distance from boiler to cylinders.

Unless a train is actually heavier than he capacity of the engine, the starting is tons accomplished by a steady pull of increased capacity, which can be more carefully and skillfully applied by the engineer, b cause each gradation in the opening of I the throttle responds at once in the cylinder pressure. After the train is started in this manner, the direct steam connection may be closed, to again force the steam from the boiler through the superheating units.

Second: lhis point of weakness in superheat engines occurring on heavy grades, is brought about by the gradual loss of the high temperatured steam through continrn ous use while the engine is exerting its maximum etl'ort. As the speed decreases, the draught necessary to continue the superheating decreases, and as a result the steam finally reaching the cylinders is of practically the same degree of heat and expansiveness as when as when it left the boiler; although it has in itself capacity for supplying a mean effective pressure in the cylinders of 93% or 941% of the boiler pressure, a loss amounting to 7% or 8% takes place, because otthe resistance engendered by retarded passage. through superheating apparatus before it can reach the cylinders.

Here again, at a time when this increased power is most needed, the full steam pressure from the boiler is sent direct to the cylinders, thereby enabling an engineer to reach the top of the grade with more surety and with increased speed.

In the'two instances just stated, i. e. starting a train and assisting a train moving up a heavy grade, the equivalent increased tractive power of an engine having a normal power of 53,000 pounds drawbar pull on a 1.25% grade, would be increased 000 pounds, which increase would move 160 tons more from a start, or on a heavy grade. Further, with this bridging or shunt connection and the use of direct steam at any time when the engine is in slow speed, a larger nozzle opening may be used during the whole trip, thus decreasing still more the amount of coal consumed. Nozzle openings with the present superheated engines are narrowed to provide for the greatest draught at the slowest speed. While this is necessary for heavy grades, and accomplishes its purpose on those grades, the smaller nozzle opening has a tendency to produce back-pressure when the engine is drifting down hill at high speed, or using steam at high speed, because the nozzle opening at that time is not large enough to permit the exhaust to pass out of the cylinders quickly. With a device that can be operated more successfully on larger opening of nozzle on heavy grades, the supreheat operation will be improved with the larger opening during the remainder of the run.

An apparatus suitable for carrying out the foregoing operations is disclosed in the accompanying drawings, wherein 'Figure 1 is a general view illustrating the type of locomotive and general arrangements of the steam system employed, with my invention incorporated therein,

Figure 2 illustrates the installation of the apparatus in the usual type of Mikado suierhcat engine,

Figure 3 is a top plan View showing the same in diagram, and

Figure 1 a detail showing a modification. l te erring to the construction in detail, 1 designates the jacket, and 2 the superheater that is connected to communicate with the dry pipe 3 that conducts the saturated steam from the boiler, and l: designates the slanting top of the superheater header, socalled, that connects the superheater header with the dry pipe.

A flue or pipe 5, of relatively short length, is connected to the side of the superheater header which opens into the discharge outlet of the dry pipe 3. Said flue or pipe is coupled by the union 6 with the two branch pipes or fiues 7 that communicate respectively with the steam passage-ways 8 extending to the steam chests 9 of the cylinders 10 (one being shown).

The fines 5 and 7 provide a bridge or shunt connection, whereby the saturated steam may be conducted directly from the saturated steam supply pipe, or the so-called dry pipe, over the superheater units, and into the steam chests of the cylinders. The control of the steam thus delivered from the boiler consists of a suitable throttle valve 11 located within the bridge connection and adapted to be operated from the cab by suitable connection with the reach-rod 12, connected with the stem or" said valve. Furthermore, it will be seen that when the main throttle is closed, the auxiliary is inoperative tor the reason that no steam is then admitted from the boiler to the dry pipe.

The addition of my improvements above described does not interfere with the action of the superheater,'tl1e passages from the boiler through the superheater and so to the engine cylinders being valveless save for the throttle valve, as is usual in locomotive engines, and therefore open whenever the throttle is open. Whenever the throttle is open therefore there will be a circulation of steam in some degree through the super-heater, though as above pointed out by far the greater volume of steam may be shunted directly to the cylinders.

While this apparatus is disclosed in connection with one particular type of engine, and with one type of superheater, it will be understood that, with slightly varying meas urements and placements, the same is adapted for any and all types of engines and superheating apparatus. Further, in the construction of new engines, or in the general overhauling of old engines, the same device may be applied in an entirely different manner, to wit:

The header of superheat apparatus has a central partition in the top. This partition serves the purpose of forcing downward the saturated steam from the dry pipe, and distributing the same through superheating units, from which it is drawn upward on the opposite side of the partition and into the cylinders.

By special design" (as suggested by illustration in Figure at), as may be best suited to the particular type of engine or superheating apparatus, in further construction of superheat headers, the auxiliary device may and should be built directly Within the header, located in the partition with the throttle connection as hereinbefore described, thus doing away with any additional pipe connections outside of the usual construction.

In operation, when starting the train from standstill, the engineer, by manipulating rod 12, can open valve 11 and thus permit the saturated steam from pipe 3 to pass directly through pipes 5, 7 and 8, to the steam chests and cylinders of the engine, thus utilizing the increased power for this purpose. When the necessity for the increased power has passed, as after the engine is in motion, or after the grade has been passed, the valve will be closed and the steam conducted through the superheat units, and its greater expansiveness thus utilized.

Having thus fully described my said invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a steam engine provided with a cab, a superheater header, a dry pipe leading thereto, a pair of pipes leading from the header to the engine cylinders, a pipe connected to the dry pipe adjacent its junction with the header, a valve in said pipe operable from the engine cab, and branch pipes extending from said pipe to the cylinder pipes, whereby the saturated steam in the dry pipe may be admitted to the cylinders to practically exclude superheated steam, substantially as set forth.

2. An engine comprising a drypipe, driving cylinders, an ever-open valveless passageway between the drypipe and the cylinders including superheating means, a direct by-pass between the drypipe and the cylinders, valve therein and means operable from the engine cab for opening and closing said valve, substantially as set forth.

In witness whereof, I have hereunto set my hand and seal at Washington, District of Columbia, this seventh day of March, A. D. nineteen hundred and sixteen.

FREDERICK XV. BROYVN. [11. s.] 

